The "Chinese Dream" is the dream of everyone in the Chinese nation, and also the dream of every primary and secondary school student. The classic reading activities carried out in primary and secondar

The "Chinese Dream" is the dream of everyone in the Chinese nation, and also the dream of every primary and secondary school student. The classic reading activities carried out in primary and secondary schools are undoubtedly the "Chinese Dream"

(1) 50 students were selected for investigation; (2) the number of B grade students was 20; (3) the degree of the central angle occupied by B grade = 144°.

Test question analysis:

(1) Divide the number of people with C grade by the percentage of C grade to get the total number of people drawn;

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(2) First subtract the number of people in grades A, C, and D from the total number of 50 to get the number of people in grade B, and then draw a line chart;

(3) Multiply by 360° The degree of the central angle occupied by B grade can be obtained by using the percentage of B grade.

Analysis of test questions: Solution: (1) 10÷20%=50,

So 50 students were selected for investigation;

(2) Level B The number of people = 50 - 15 - 10 - 5 = 20 (people),

Draw a broken line statistical chart;

(3) The degree of the central angle occupied by level B in Figure B = 360°× =144°.